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<div role="main"><h1>Adding watchpoints</h1>

<p>A watchpoint is a special breakpoint that stops the execution of an 
application whenever the value of a given expression changes, without specifying 
where it might occur. Unlike breakpoints (which are line-specific), watchpoints 
are associated with files. They take effect whenever a specified condition is 
true, regardless of when or where it occurred. You can set a watchpoint on a global variable by highlighting the variable in the editor, or by selecting it in the Outline view. </p>

<p>To set a watchpoint on a global variable:</p>

<ol>
  <li>Highlight the variable in the editor, or select it in the Outline view.</li>
  <li>Click <strong>Run &gt; Toggle Watchpoint</strong>.</li>
  <li>Do any of the following:
  <ul><li>To stop execution when the watch expression is read, select the
  <strong>Read</strong> check box.</li>
  <li>To stop execution when  the watch expression is written to, select the <strong>Write</strong> 
  check box.</li></ul>
  </li>
  <li>The watchpoint appears in the <strong>Breakpoints</strong> view 
  list.</li>
</ol>

<p><img src="../images/ngconcepts.gif" ALT="Related concepts" width="143" height="21">
<br>
<a href="../concepts/cdt_c_over_cdt.htm">C/C++ Development perspective</a></p>
<p><img src="../images/ngtasks.gif" ALT="Related tasks" width="143" height="21">
<br>
<a href="cdt_o_brkpnts_watch.htm">Using breakpoints and watchpoints</a></p>
<p><img src="../images/ngref.gif" ALT="Related reference" width="143" height="21">
<br>
<a href="../reference/cdt_o_run_dbg_pages.htm">Run and Debug dialog box</a></p>

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